[molpro-user] Calculation for excited Ne+

[Enrico Bodo]

Questo input funziona, ma non potrai fare CI a meno che tu non usi
l'opzione "noexc" cioe' di fatto ricalcoli la configurazione CAS di
riferimento. Pero' se tu volessi usare i programmi legati a CI come lo
spin-orbita potrai farlo al livello MCSCF usando quell'opzione.

*** Titolo

gprint,basis
gprint,orbital

basis, vdz

geometry={
Ne       0.000000        0.00000        0.00000
}

{rhf;wf,10,1,0; core,0,0,0,0,0,0,0,0; occ,2,1,1,0,1,0,0,0}

{rhf, nitord=1; wf,9,1,1; rotate,1.1,2.1,0; core,0,0,0,0,0,0,0,0;
occ,2,1,1,0,1,0,0,0; open, 1.1;}

put,molden,p.molden

{multi;
frozen,0,0,0,0,0,0,0,0;
closed,0,0,0,0,0,0,0,0;
occ,2,1,1,0,1,0,0,0;
freeze,2.1;
restrict,1,1,2.1
wf,9,1,1}

---



2013/5/9 Lorenzo Lodi <l.lodi at ucl.ac.uk>

> Hello, thank you all for your suggestions. Unfortunately I haven't yet
> been able to compute the energy of this core-hole state with MRCI.
> I can get the energy with CASSCF by doing something like:
>
> {RHF; WF,nelec=9,symmetry=1,spin=1; ORBPRINT,0}
> {CASSCF; OCC, 2,1,1,0,1,0,0,0; CLOSED,0,0,0,0,0,0,0,0;
> FROZEN,0,0,0,0,0,0,0,0;
> {ITERATIONS;
> DONT  , WERNER  , 1, TO, 20;
> }
> WF,nelec=9,symmetry=1,spin=1; state,1
> SELECT
> CON, 1,2,2,2,2
> }
>
>
> The first RHF converges to (1s)^2 (2s)^1 (2p)^6; in the following CASSCF
> I (I try to) select as only allowed configuration the one where the
> lowermost orbitals is singly occupied;
> nonetheless, if I allow optimization of the orbitals I get back to the
> same configurations as given by the RHF state...
> When I try to do MRCI using the CASSCF wavefunction above either I get
> error messages or I never get the energy I want.
>
>
> On 07/05/13 01:57, Terry Frankcombe wrote:
> > Why not simply do the RHF for the neutral, then start selecting configs
> > for the CI?
> >
> > Converging the core hole state should certainly be possible.  But it may
> > require a largish multi-state CI.  (Speaking off the top of my head
> > here.)
> >
> >
> > On Mon, 2013-05-06 at 17:25 +0100, Lorenzo Lodi wrote:
> >> I would like to compute the energy (using Hartree-Fock and then
> >> configuration interaction) of an excited state of the Ne+ atomic ion
> >> with configuration  (1s)^1 (2s)^2 (2p)^6.
> >> I tried
> >> {UHF; WF,nelec=9,symmetry=1,spin=1; occ,2,1,1,0,1; open, 1.1;
> ORBPRINT,0}
> >>
> >> which seems to work, and produces approximately the correct energy
> >> (about 31 hartrees above the ground state of Ne+).
> >> On the other hand, the same input using RHF
> >> {RHF; WF,nelec=9,symmetry=1,spin=1; occ,2,1,1,0,1; open, 1.1;
> ORBPRINT,0}
> >>
> >> converges to the ground state, as if the `open, 1.1' command was
> >> ignored. However, if I do UHF and then RHF using UHF orbitals as
> >> starting guess then RHF also goes to the correct state. Any comments?
> >>
> >> When I try to use the RHF orbitals for MRCI ( CISD in this case)
> >> {MRCI; WF,nelec=9,symmetry=1,spin=1; STATE,1}
> >>
> >> I get the error message:
> >> CI VECTOR FOR STATE 1 DOES NOT OVERLAP SUFFICIENTLY WITH REFERENCE
> VECTORS
> >> It may help to increase NSTATI, e.g., use OPTION,NSTATI=2
> >>
> >> Setting NSTATI=2 gives the error
> >> MORE STATES THAN REFERENCE CONFIGURATIONS:     2    1
> >>
> >>
> >> What can I do to have MRCI to converge on the correct state?
> >>
> >> Lorenzo
> >>
> >>
> >> _______________________________________________
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> >> http://www.molpro.net/mailman/listinfo/molpro-user
> >
> >
>
>
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-- 
Enrico Bodo  -  Assistant Professor in Theoretical Chemistry
"La Sapienza" University of Rome
Department of Chemistry
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